类型为“可观察”的属性“捕获”不存在 <IEmployee[]> &#39;.ts（2339）通过添加导入&#39;rxjs / add / operator / catch&#39;无法解决错误；

Question

当我将鼠标悬停在.catch(this.errorHandler) ，我收到一条错误消息

类型'Observable'.ts（2339）上不存在属性'catch'

我无法将catch函数导入角型打字稿。

当我将鼠标悬停在.catch(this.errorHandler) ，我收到一条错误消息

类型'Observable'.ts（2339）上不存在属性'catch'

根据另一个堆栈文章： 属性'catch'在类型'Observable <any>'中不存在，我应该添加：

import 'rxjs/add/operator/catch'

我也尝试导入

import {Observable} from 'rxjs/Rx';

和

import { catchError } from 'rxjs/operators'; 

并使用catchError代替catch。

这些都不起作用

    import { Injectable } from '@angular/core';
    import { HttpClient, HttpErrorResponse } from '@angular/common/http';
    import { IEmployee } from './employee';
    import { Observable, fromEventPattern } from 'rxjs';
    import 'rxjs/add/operator/catch';
    import {catchError} from "rxjs/operators"
    import 'rxjs/add/observable/throw';

    @Injectable({
      providedIn: 'root'
    })
    export class EmployeeService {

      private _url : string = "../assets/data/employees.json";
      constructor(private http: HttpClient) { }

      getEmployees(): Observable<IEmployee[]>{
        return this.http.get<IEmployee[]>(this._url)
                        .catch(this.errorHandler)
      }
      errorHandler(error:HttpErrorResponse){
          return Observable.throw(error.message ||"Server Error")
      }
    }

Answer 1

两个问题：

1. 使用catchError不能catch

2. 与.pipe（）一起使用

     return this.http.get<IEmployee[]>(this._url) .pipe(catchError(this.errorHandler)); 

Answer 2

试试看（catchError和throwError）：

import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import { IEmployee } from './employee';
import { Observable, fromEventPattern, throwError} from 'rxjs';
import {catchError} from "rxjs/operators"

@Injectable({
  providedIn: 'root'
})
export class EmployeeService {

  private _url : string = "../assets/data/employees.json";
  constructor(private http: HttpClient) { }

  getEmployees(): Observable<IEmployee[]>{
    return this.http.get<IEmployee[]>(this._url)
                   .pipe(catchError(this.handleError));
  }

   handleError(error: HttpErrorResponse) {

     //throwError instead of Observable.throw
      return throwError(error.error.message ||"Server Error");
  };
}